Aircraft



mMmh 26, 1946. E. A. STALKER 2,397,215

I AIRCRAFT Filed May 13, 1945 /Nf/ENTOQ a F16. 9 j

Patented Mar. 26, 1946 UNITED STATES PATENT FFICE AIRCRAFT Edward A. Stalker, Bay City, Mich.

Application May 13, 1943, Serial No. 486,791

3 Claims.

My invention relates to wing structures for boundary layer control wings and has for its objects, rst, to provide a firm and substantial wing structure having slots for inducting the boundary layer and providing for an internal flow from the suction slots with a minimum power loss; and

second, to provide such a structure having discharge slots which will accommodate a ow to the discharge slot with little loss of energy while alfording proper strength and stability. `Other objects will appear from the description and drawing.

In providing wings with serially hinged flaps, as disclosed in my application, Serial Number 313,967 filed January 15, 1940, difculty has heretofore been encountered in providing a suitable passage way for the inducted air whileproviding at the same time a structure adequate to carry the lift, drag and other loads encountered in operation. Contemporary thought has suggested simply to punch circular or other-shaped holes in the web of the spars. This practice would be very wasteful of energy in any case because of the rapid expansion of the downstream side of the web, but when the volume handled becomes large, it is prohibitive.

I have devised a type of structure which permits a large volume ow from the suction slots, and a large volume flow to the discharge slots, both with a negligible or exceptionally small loss of energy within the wing, while at the same time the structure may be made of adequate strength and with substantial freedom of designl to support such loads as are encountered.

I attain the objects of the invention by the means illustrated in the figures in which:

Fig. 1 is a plan view of a preferred wing;

Fig. 2 is front view of the wing;

Fig. 3 is a section along the lines 3 3 in Figs. 1 and 2l with the flaps depressed;

Fig. 3a is an outline view similar to Fig. 3 vbut with the flaps raised;

Fig. 4 is a detail sectional view along lines llin Fig. 1;

Fig. 5 is a sectional View along the line 5 5 in Fig. 1;

Fig. 6 is a detail sectional view along line 6 5 in Fig. 3;

Fig. 7 is a fragmentary elevation of the rear spar of the preferred wing viewed from the nose of the wing; y

Fig. 8 is a section along the line 8 8 in Fig. 7; Fig. 9 is a section along line 9 9 in Fig. '7; and Fig. 10 is a fragmentary elevation of a modified spar type.

Each of the wings I is comprised of the main body 2 and the flaps 3 and suitably arranged in tandem relation and adjustably mounted with respect to each other and to the wing main body. Th'e upper surface of the main body and of each of the flaps is provided with a generously curved surface having a substantial radius of curvature,

in excess of the thickness of the wing adjacent thereto. This provides the scalloped appearance of the wing in the raised position of the aps, and provides for establishing a highly cambered Wing with a substantially smooth and continually curved upper surface when the fiaps are deL pressed. As shown they may be depressed to defleet the relative wind through an angle of up to approximately Outwardly of flap 4 and adjustably secured at the trailing endof forward iiap 3 is the aileron 5. The aileron is constructed similarly to the flap 4, and has a similarly curved upper surface. It is arranged to be controlled by the pilot, separately from the fiaps with the ailerons on opposite Wings being differentially actuated while the controls for the lift flaps 3 and 4 on opposite wings pro vide for similar actuation thereof. f

A'blower 6 is provided which islocated at a suitable position within th'e hollowY wing and serves to induct the boundary layer on the Wing surfaces. This is effected through the provision of upper surface slots l, 8 and 9. Slot 'IV is located adjacent the trailing end of the wing main-body and the leading end of lift flap 3. Slot 8 is preferably located adjacent the trailing end of flap 3 and the leading ends of the ap 4 and th'e aileron 5, respectively. Slot 9 is preferably located adjacent the rearmcst portion of the upper wing surface comprising flap 4 and aileron 5.

boundary layer on the portions of the Wingin advance of the respective slots, thereby causing the relative VWind to follow the wing contour.Y

With a wing constructed to have the high camber as shown in Fig. 3, for example where the relative wind is deflected through an angle of approximately 90 degrees, it is desirable to provide a smooth and relatively clear and uninterrupted path of iiow for the air passing through the slot and the wing interior. This isfor the reason that a large volume of flow is desired to be attained, particularlyy in the high lift position of the wing as shown in Fig. 3, and unless the resistance to such flow is reduced, there is a substantial loss ofenergy by reason of the internal resistance to such ow. Y y

Likewise it is necessary to have a rigid spar construction at the rear of the wing main body to provide the necessary strength and rigidity to sustain the loads from theaps. While requiring this substantial mechanical construction, the freedom of airflow through the structure must likewise be attained.

A form of spar construction for this purpose is shown generally at I0, and comprises chord mem# bers Ilia extending spanwise of thewing adjacent the upper and lower surfaces thereof. The

chord members Illa are preferably oval shaped I tubes suchas shown in Fig. 9, with the lattice These slots severally provide for the induction of the members II and I2 being ofstreamlined shape substantially as shown in Fig. 8. Preferablythe major axis of the cross-section of both chord and lattice members .is .generally `.aligned `with the local flow direction 'which varies along lthespan, but can be determined readily with threads or with a directionometer.

An alternative arrangement'is shown in Fig, 10 where the chord members and the vertical supports are the same as described above,butin which the lattice members are replaced 'by streamlined wires I3. y

At the locality Where the lift struts IA and l5 attach, a rigid frame is formed chordwise to con- ,fer drag :and torsional, rigidity .fon :the tubeli-ke structurerformed'by.the front-an'dxear sparszand thea-:upper and lower Veoversz-of thawing. "The diagonal .I6 yhas the streamline :shape izas show-n LEig. 1 6. .The itop fand :bottom .members .IFI fand =.Ia8 :.of'ithis frame have `,thea crossfsectional shape as shownfin-Figf.

The V charmelflilse ymembersl ft] :and Ij-have :a

shallow'` depth sogas .to @present af-streamline form lloi? kthe :rib :may be joined to the :adjacent-skin either by Weldingfriveting `for -in any Yother suit- .able manner.

.The `blowerft :is arranged -to discharge vvinto a duet :I9 lwhich `fleads :from the blower 'outwardly valmrgrtlfie :leadingedgezof the wing'to the outer .endfthereo A partition *wall .Zl .formed lin Athe vvertical.planefoi the forward .chord members 'Ita and immediately :above strut -,I5 ,.;provides ,-for f.

segregating fthe :flow passage .through which @the ,discharge :takes lplace. The 4front spar f2I termihatesinboard .fromthe :wing tips as :shown in Fig.;1. :Because ofV the taper of the -Wing :thickness, the duct decreases :in Ydepth Voutwardly to- 1 wardfthe tip, tand ari-auxiliary yWall 19a is providedags shown in l1'. ig.-..5 to vvconfirm-passage -I'S ito the Yflower portion :of the iwing Vcross-section. v-A exiblefelement 2-3 tof rubber .or the ,flike :forms `:a tube with the lower rWall ;of the wing? -to -which it i-sncemented, ,providing a :continuous -fclosed' passagerleading :from1duct 1,9 to the duct 22 within nap s3. Anioutlet Ydischarge .slotvzgadiacentrthe trailing end 'of' flap .3 provides :for fthe discharge oftheiaair'del-ivered ahy-)the blower on .the ',.lower sideof the wing. 1

'The interiorzof the ming isrdividedlinfa special manner.Y -The :forward partition or spar 2I, and the :additionalmartition 'Z6 and :21 fextend .in spaced relation to each other across the -toptof blower-f6 Where theyare -notchedetor-aceommodate the blower. These partitions @divide the :blower inlet area by cutting across the same endsegregating it :into gportions 1 approximately proportionalztoithelengthofthe-'slotto,befserved .Thus partitionlZS .f'denes a 'orwardypcrticn of .the

\ blowerinletarea irlfiiclirisproportioned.approxi-y mately 'tothewareaiof slots 1, Bandi-9 between v.the

wing tip and the terminationzof gpa-rtitioneZron therchordwise line ,extendmg :across theslots .be-

tween 'Lth'e .aends thereof. .'Jhe Vportion f of -the and 21 and extending across the slots. The rear portion of the blower inlet area is proportioned to the slot areas inboard of the outer end of partition 2'I. l

.It isnotnecessary that the severalpartitions extend to the trailing edge of the wing or even finto the space directly beneath the surface slots of the wing.` It is found desirable to have the Y"partitions terminate forwardly of the slots with some space vprovided aft thereof for free circulation, to afford some spanwise adjustment of the static rl`pressure within thewing, as may be Yrequired. It is important, however, that the partitions terminate at stations successively further towards' .thetipzinprogressing from' -the:rear;parY titiontoward theorward partition.

.By dividing ithe wing in this -manneifthetbest distribution .zofz suction .is .attained along .fthefspan .of .the :wing :and przovides ysubstantially :improved flow and distribution, .being marticularlysmore 'desirable'thanthe `throttling precedures heretofore suggested. i

*While'theformszofzapparatusiereinadessibed Y constitute fpre'ferred :embodiments Ylof fitheiinveny Y 1.In combination, La-Lyving fmain 'bodyitarrcheJ relation with saidwin'g, said "wingxhayingjaslot f in its surface, means tto Y.produce ;a-.1oWlof :air through said slot and spanwise through fthefwin'g interior, and Va structural #member l'extending chordwise withinzsaid wing/fhavingaecross secmum rise of 'the exterior lcontour soiisaid` aarched section being substantially less thanthejidowmstream extent :of Jsaidsarched fcontour.

2.'In combination, 'a hollow "Wingfhavirrg ,asslot Y in its surface extendingspanmnse .thereof and leading into thewng'interioniblower means hay ing fa 'now :passage 1in cpmnrmication with :said

wing interior and through said islota partition Within said wing extendingracrossfsaidzlow passage l"and span-wise along :said 'Wing toia Idlfiorld-V wise linerext'ending across fsaids'lotbetweentlie ends thereof, said `partition fdividingithe areagof said -ow passage into ycormiioI-ient `areaswhich K are substantially*proportional respectively to the areas of the segments of said -slot von each-"side of vsaid line to provide for regulated A'flow di '-air through said slot-throughout 'the extent Ithereo'i, said partition terminating shortpi 'said 's'lotleaving ha free circulation space within which"adjust;-k ment of the static pressure 'within `'said wing'may occur. 4

3. In combination, a 'hdll'cw wing havmg a 'slot in its surface `extending .spanwise thereof and leading into the wing interiorjb'lcwermeanshaving -its inlet 'in communication with 'said wing' interior to .induce a .ow .ofair into the 'winggiinterior throughsaid slot,l aplurality of partitions f within said .wing extending across "sa'id Kinlet to divide Vit into a plurality oi component' areas, said plurality .of l.partitions extending fspanwise ci v.the wing and .terminating lin succession 1spanwise at increasingdistances .from-.said 'inlet area forming `.a series -of .open ended and clear and unobstructed flew passages.

EDWARDA STALKER. 

